It has been well established that the recovery ability of central nervous system （CNS） is very poor in adult mammals. As a result, CNS trauma generally leads to severe and persistent functional deficits. Thus, the i...It has been well established that the recovery ability of central nervous system （CNS） is very poor in adult mammals. As a result, CNS trauma generally leads to severe and persistent functional deficits. Thus, the investigation in this field becomes a ＂hot spot＂. Up to date, accumulating evidence supports the hypothesis that the failure of CNS neurons to regenerate is not due to their intrinsic inability to grow new axons, but due to their growth state and due to lack of a permissive growth environment. Therefore, any successful approaches to facilitate the regeneration of injured CNS axons will likely include multiple steps： keeping neurons alive in a certain growth-state, preventing the formation of a glial scar, overcoming inhibitory molecules present in the myelin debris, and giving direction to the growing axons. This brief review focused on the recent progress in the neuron regeneration of CNS in adult mammals.展开更多
Planarian is among the simplest animals that possess a centralized nervous system （CNS）, and its neural regenera- tion involves the replacement of cells lost to normal ＇wear and tear＇ （cell turnover）, and/or inj...Planarian is among the simplest animals that possess a centralized nervous system （CNS）, and its neural regenera- tion involves the replacement of cells lost to normal ＇wear and tear＇ （cell turnover）, and/or injury. In this review, we state and discuss the recent studies on molecular control of neural regeneration in planarians. The spatial and temporal expression patterns of genes in intact and regenerating planarian CNS have already been described relatively clearly. The bone morphogenetic protein （BMP） and Wnt signaling pathways are identified to regulate neural regeneration. During neural regeneration, conserved axon guidance mechanisms are necessary for proper wiring of the nervous system. In addition, apoptosis may play an important role in controlling cell numbers, eliminating unnecessary tissues or cells and remodeling the old tissues for regenerating CNS. The bilateral symmetry is established by determination of anterior-posterior （A-P） and dorsal-ventral （D-V） patterns. Moreover, neurons positive to dopamine, serotonin （5-HT）, and gamma-aminobutyric acid （GABA） have been detected in planarians. Therefore, planarians present us with new, experimentally accessible contexts to study the molecular actions guiding neural regeneration.展开更多
After 2/3 transection of the right ninth thoracic spinal cord of an adult rat, a chitosan tube seeded with L-poly-lysine was implanted between the rostral and caudal end of the lesioned cord. Twelve months after the o...After 2/3 transection of the right ninth thoracic spinal cord of an adult rat, a chitosan tube seeded with L-poly-lysine was implanted between the rostral and caudal end of the lesioned cord. Twelve months after the operation, regeneration of myeli-nated and non-myelinated axons and new blood vessels were observed along the wall of the chitosan tube implanted under an electron microscope. Somatosensory evoked potentials (SEP) could be consistently recorded from the left somatosensory cortex following electrical stimulation of the right hind limb, while transcranial magnetic stimulation of the left motor cortex could also evoke motor activity from the right hind limb. The present result suggests that implanted chitosan tube might be useful in regenera-tion of injured nerve fibers of the spinal cord resulting in a long-term restoration of motor functions.展开更多
The limited regenerative capacity of several organs, such as central nervous system(CNS), heart and limb in mammals makes related major diseases quite difficult to recover. Therefore, dissection of the cellular and mo...The limited regenerative capacity of several organs, such as central nervous system(CNS), heart and limb in mammals makes related major diseases quite difficult to recover. Therefore, dissection of the cellular and molecular mechanisms underlying organ regeneration is of great scientific and clinical interests. Tremendous progression has already been made after extensive investigations using several model organisms for decades. Unfortunately, distance to the final achievement of the goal still remains. Recently, zebrafish became a popular model organism for the deep understanding of regeneration based on its powerful regenerative capacity, in particular the organs that are limitedly regenerated in mammals. Additionally, zebrafish are endowed with other advantages good for the study of organ regeneration. This review summarizes the recent progress in the study of zebrafish organ regeneration, in particular regeneration of fin, heart, CNS, and liver as the representatives. We also discuss reasons of the reduced regenerative capacity in higher vertebrate, the roles of inflammation during regeneration, and the difference between organogenesis and regeneration.展开更多
基金supported by the National Natural Science Foundation of China(No.30571909,No.30872666)the Youth Teacher Foundation of Jiangsu Pro-vince(No.BU134701)China,and the Medical Development Foundation of Soochow University(No.EE134615)
文摘It has been well established that the recovery ability of central nervous system （CNS） is very poor in adult mammals. As a result, CNS trauma generally leads to severe and persistent functional deficits. Thus, the investigation in this field becomes a ＂hot spot＂. Up to date, accumulating evidence supports the hypothesis that the failure of CNS neurons to regenerate is not due to their intrinsic inability to grow new axons, but due to their growth state and due to lack of a permissive growth environment. Therefore, any successful approaches to facilitate the regeneration of injured CNS axons will likely include multiple steps： keeping neurons alive in a certain growth-state, preventing the formation of a glial scar, overcoming inhibitory molecules present in the myelin debris, and giving direction to the growing axons. This brief review focused on the recent progress in the neuron regeneration of CNS in adult mammals.
基金the Southeast University Foundation for Excellent Young Scholars (No. 4023001013)the Program for New Century Excellent Talents in University.
文摘Planarian is among the simplest animals that possess a centralized nervous system （CNS）, and its neural regenera- tion involves the replacement of cells lost to normal ＇wear and tear＇ （cell turnover）, and/or injury. In this review, we state and discuss the recent studies on molecular control of neural regeneration in planarians. The spatial and temporal expression patterns of genes in intact and regenerating planarian CNS have already been described relatively clearly. The bone morphogenetic protein （BMP） and Wnt signaling pathways are identified to regulate neural regeneration. During neural regeneration, conserved axon guidance mechanisms are necessary for proper wiring of the nervous system. In addition, apoptosis may play an important role in controlling cell numbers, eliminating unnecessary tissues or cells and remodeling the old tissues for regenerating CNS. The bilateral symmetry is established by determination of anterior-posterior （A-P） and dorsal-ventral （D-V） patterns. Moreover, neurons positive to dopamine, serotonin （5-HT）, and gamma-aminobutyric acid （GABA） have been detected in planarians. Therefore, planarians present us with new, experimentally accessible contexts to study the molecular actions guiding neural regeneration.
基金supported by the National Natural Science Foundation of China(Grant No.30330220)Natural Key Foundation Program of Beijing(Grant No.7041002),National 863 Project(Grant No.2005AA205)Key Project of Science and Technology Department of Beijing,China(Grant No.H020920040430).
文摘After 2/3 transection of the right ninth thoracic spinal cord of an adult rat, a chitosan tube seeded with L-poly-lysine was implanted between the rostral and caudal end of the lesioned cord. Twelve months after the operation, regeneration of myeli-nated and non-myelinated axons and new blood vessels were observed along the wall of the chitosan tube implanted under an electron microscope. Somatosensory evoked potentials (SEP) could be consistently recorded from the left somatosensory cortex following electrical stimulation of the right hind limb, while transcranial magnetic stimulation of the left motor cortex could also evoke motor activity from the right hind limb. The present result suggests that implanted chitosan tube might be useful in regenera-tion of injured nerve fibers of the spinal cord resulting in a long-term restoration of motor functions.
文摘The limited regenerative capacity of several organs, such as central nervous system(CNS), heart and limb in mammals makes related major diseases quite difficult to recover. Therefore, dissection of the cellular and molecular mechanisms underlying organ regeneration is of great scientific and clinical interests. Tremendous progression has already been made after extensive investigations using several model organisms for decades. Unfortunately, distance to the final achievement of the goal still remains. Recently, zebrafish became a popular model organism for the deep understanding of regeneration based on its powerful regenerative capacity, in particular the organs that are limitedly regenerated in mammals. Additionally, zebrafish are endowed with other advantages good for the study of organ regeneration. This review summarizes the recent progress in the study of zebrafish organ regeneration, in particular regeneration of fin, heart, CNS, and liver as the representatives. We also discuss reasons of the reduced regenerative capacity in higher vertebrate, the roles of inflammation during regeneration, and the difference between organogenesis and regeneration.
